Cut the tofu into 1 cm cubes and finely chop the leeks and cilantro.
Add vegetable oil to a pot and saute the leeks and cilantro on low heat until slightly browned.
Add the ingredients marked ● and increase to high heat. When it comes to a boil, remove from heat.
Add 1 tablespoon water with dissolved katakuriko to the pot, mix well, then return to high heat. Remove from heat right before it starts to boil, add sesame oil and Aji-no-moto seasoning, then mix.
Serve to individual bowls, garnish with cilantro leaves, then serve.
Note: For those who dislike cilantro, substitute with other garnishing, such as mitsuba (Japanese parsley), scallions, Chinese citrus zest, or shiso leaves.
Story Behind this Recipe
I prepare this soup regularly. Why not have a bowl?
1) Be sure to remove the pan from heat before adding the potato starch dissolved in water. Mix before returning to high heat, but remove from heat again right before it comes to a boil. Soup thickened with potato starch should not be boiled. 2) When I'm on a diet, I have this soup every other meal. With only 130 calories per bowl (with 4 servings), it's actually very filling!